1. Field of the Invention
The present invention relates to an electrically-bent endoscope for electrically bending a bending portion.
2. Description of the Related Art
Conventionally, endoscopes have been widely used. The long and narrow inserting portion of an endoscope can be inserted to the body cavity in order to observe the internal organs and to treat the internal organs as required by using treating devices laid within a treating device channel. Furthermore, the long and narrow inserting portion of an endoscope is inserted in order to observe and examine the wear and tear and/or corrosion inside of a boiler, a turbine, an engine or a chemical plant.
A bendable bending portion is connected to the base end side of the head of the long and narrow inserting portion of this kind of endoscope. A bending operation input portion such as a bending operation lever and a joystick in an operating portion is operated in order to instruct to the endoscope the bending position and bending speed of the bend as an amount of bending. In the endoscope, the bending operation wires are mechanically pulled or relaxed based on the instructed amount of bending so as to bend the bending portion.
This kind of endoscope has been proposed as an electrically-bent endoscope as disclosed in Japanese Unexamined Patent Application Publication No. 4-256724 previously filed by the present applicant, for example. The proposed electrically-bent endoscope has the bending portion electrically bent by controlling the rotation of the contained motor and by pulling or relaxing the bending operation wires by using the motor driving force.
The electrically-bent endoscope disclosed in Japanese Unexamined Patent Application Publication No. 4-256724 has a clutch mechanism for turning the driving force of the motor off. The clutch mechanism shuts off the transmission of the driving force of the motor, thus enables the bending portion to be in the angle-free mode.